Glycoprotein hormone compositions containing two β subunits

ABSTRACT

Forms of differentially acting glycoprotein hormones are disclosed. These compositions are of the formula
 
β 1 -(linker 1 ) m -α-(linker 2 ) n -β 2 ;  (1)
 
β 1 -(linker 1 ) m -β 2 -(linker 2 ) n -α;  (2)
 
α-(linker 1 ) m -β 1 -(linker 2 ) n -β 2 ;  (3)
 
β 2 ≈α-(linker) m -β 1 ; or  (4)
 
β 1 -(linker) m -α≈β 2   (5)
 
     wherein each of β 1  and β 2  has the amino acid sequence of the β subunit of a vertebrate glycoprotein hormone or a variant of said amino acid sequence, as variants are defined herein. “α” designates the α subunit of a vertebrate glycoprotein hormone or a variant thereof, “linker” refers to a covalently linked moiety that spaces the β 1  and β 2  subunits at appropriate distances from the α subunit and from each other. “≈” is a noncovalent link. Each of m and n is independently 0 or 1.

This Application is a continuation of U.S. Ser. No. 09/175,017, filed 19Oct. 1998, and now U.S. Pat. No. 6,635,256. The contents of thisdocument are incorporated herein by reference.

ACKNOWLEDGMENT OF GOVERNMENT SUPPORT

This invention was made in part with government support under NIHContract No. NO1-HD-9-2922, awarded by the National Institutes ofHealth. The government has certain rights in this invention.

CROSS REFERENCE

This application is a continuation-in-part of the U.S. Ser. No.08/971,439, filed 17 Nov. 1997, the contents of which are incorporatedherein by reference

TECHNICAL FIELD

The invention relates to the field of protein engineering, specificallyto modified forms of certain glycoprotein hormones which native formsoccur normally as heterodimers. The invention concerns multiple domaincomplexes of chorionic gonadotropin (CG), thyroid stimulating hormone(TSH), luteinizing hormone (LH), and follicle stimulating hormone (FSH),wherein an a subunit covalently linked to a β subunit may associate withan additional β subunit or may be covalently linked to two β subunits.These multiple domain glycoprotein hormones can provide two or moreeffects or functions, or can behave like agonists and/or antagonists ofthe native hormones.

BACKGROUND ART

In humans, four important glycoprotein hormones (LH, FSH, TSH and CG)are heterodimers that have identical a subunits and differing βsubunits. Three of these hormones are present in virtually all othervertebrate species as well; CG has so far been found only in primatesand in the placenta and urine of pregnant mares.

PCT application WO90/09800, published 7 Sep. 1990, and incorporatedherein by reference, describes a number of modified forms of thesehormones. One important modification is C-terminal extension of the βsubunit by the carboxy terminal peptide (CTP) of human chorionicgonadotropin or a variant thereof. Other muteins of these hormones arealso described. CTP is the sequence of amino acids extending from anyone of positions 112-118 to position 145 of the β subunit of humanchorionic gonadotropin. The PCT application describes variants of theCTP extension obtained by conservative amino acid substitutions suchthat the capacity of the CTP to alter the clearance characteristics ofthe hormone is not destroyed. In addition, PCT application WO94/24148published 27 Oct. 1994, incorporated herein by reference, describesmodifying these hormones by extension or insertion of the CTP atlocations other than the C-terminus and CTP fragments shorter than thesequence extending from positions 112-118 to 145.

The CTP-extended β subunit of FSH is also described in two papers byapplicants herein: LaPolt, P. S. et al.; Endocrinology (1992)131:2514-2520 and Fares, F. A. et al.; Proc Natl Acad Sci USA (1992)89:4304-4308. Both of these papers are incorporated herein by reference.

The crystal structure of human chorionic gonadotropin has been publishedin more or less contemporaneous articles; one by Lapthorn, A. J. et al.Nature (1994) 369:455-461 and the other by Wu, H. et al. Structure(1994) 2:545-558. The results of these articles are summarized by Patel,D. J. Nature (1994) 369:438-439.

PCT application WO91/16922 published 14 Nov. 1991 describes amultiplicity of chimeric and otherwise modified forms of theglycoprotein hormones. In general, the disclosure is focused on chimerasof α subunits or β subunits involving portions of various α or β chainsrespectively. One construct simply listed in this application, and nototherwise described, fuses substantially all of the β chain of humanchorionic gonadotropin to the β subunit preprotein, i.e., including thesecretory signal sequence for this subunit.

Two additional published PCT applications describe single-chain forms ofthese glycoprotein hormones wherein the α and β subunits are covalentlylinked to result in a compound of the general formula:β(linker)_(n)α;orα(linker)_(n)β

wherein n is 0 or 1 and α and β represent the respective subunits ofthese hormones: Moyle, W. R., PCT application WO95/22340 published 24Aug. 1995 and the application of the inventor herein, WO96/05224published 22 Feb. 1996. The disclosure of these documents is alsoincorporated herein by reference.

Forms of the above-described single-chain forms of these hormones inwhich the number of cystine bridges has been depleted are disclosed inU.S. Ser. No. 08/933,693 filed 19 Sep. 1997, and incorporated herein byreference.

The α subunit of a single-chain form of a glycoprotein hormone, CGβ-α,was found to bind noncovalently to an FSHβ subunit as disclosed by theapplicants in Society for the Study of Reproduction, Abstract 193, 1996.

Recently, the α subunit of the single-chain glycoprotein hormone,FSHβ-α, was found to form a noncovalent link with a GCβ subunit asdisclosed by the applicants in Endocrine Society, Abstract OR28-3, 1998.

It has now been found possible to use these glycoprotein hormones whichhave enhanced agonist and/or antagonist activity and/or which aremulti-functional by either covalently linking an additional β subunit toa single-chain hormone or noncovalently linking an additional β subunitto the tethered α subunit of a single-chain hormone to mimic a naturalhormone profile and/or control hormone ratios. These differentiallyacting glycoprotein hormones and their therapeutic uses for treatingdisorders such as polycystic ovarian disease, infertility, and ovarianhyperstimulation are disclosed hereinbelow.

DISCLOSURE OF THE INVENTION

The invention provides differentially acting glycoprotein hormonescontaining an α subunit covalently linked to a β subunit to form asingle-chain hormone and an additional β subunit either covalentlylinked to the single-chain hormone or noncovalently linked to thetethered a subunit of the single-chain hormone. The compositions of theinvention may either be glycosylated, partially glycosylated, ornonglycosylated and the fused α and β chains that occur in the nativeglycoprotein hormones or variants of them may optionally be linkedthrough a linker moiety. Particularly preferred linker moieties includethe carboxy terminal peptide (CTP) unit either as a complete unit or avariant including variants which represent only a portion thereof.

If the β subunits are the same, the compositions containing anoncovalently linked β subunit can act as agonists or antagonists, butthe degree of activity may vary with time. This variation in theactivity is due to the difference between the circulating half-lives ofthe covalently linked and the noncovalently linked β subunits. Thecirculating half-life of the noncovalently linked β subunit willinherently be shorter than that of the β subunit covalently linked tothe α subunit. This is due to dissociation of the complex over time inthe physiological environment; however, the covalently linked portion ofthe molecule remains an effective pharmaceutical.

For example, a composition having a FSHβ subunit covalently linked to anα subunit which is noncovalently linked to another FSHβ subunit wouldhave a greater activity during the circulating half-life of the complex.However, the activity would decrease after the shorter half-life of thenon-tethered FSHβ subunit ends.

A composition having a FSHβ subunit covalently linked to an α subunitwhich is noncovalently linked to a CGβ subunit would exhibit a longercirculating half-life for FSH activity and a shorter circulatinghalf-life for CG activity. For the duration of the shorter circulatinghalf-life, both the FSHβ and CGβ subunits would act upon theirrespective receptors. During the longer half-life, only the FSHβ subunitcovalently linked to the α subunit would be active.

In all cases, if the β subunits are different, the compositions arebifunctional as agonists and/or antagonists. It will be noted thatdifferential ratios of activity can be obtained by increasing ordecreasing the agonist activity of one component relative to the other.For example, one could enhance the FSH/LH ratio by utilizing an FSHsubunit with enhanced agonist activity and/or an LH subunit withdecreased agonist activity.

In one aspect, the invention is directed to a method to providedifferent glycoprotein hormone activities to a subject in need ofhormone regulation.

By a glycoprotein hormone “activity” is meant the ability to behave asan agonist or antagonist of a corresponding native hormone with the sameor different biological half-life. Thus, “two different glycoproteinhormone activities” means that the activities conferred on thecomposition by each β subunit differ in one or more ways. One may be anagonist, the other an antagonist; one may be modified so as to provideenhanced activity; one may be modified so as to provide reducedactivity; one may correspond to the activity of LH and the other to thatof FSH, or one may have a long circulating half-life and the other ashorter circulating half-life. Thus, by providing different native βsubunits in the compositions of formulas (1)-(5) or by providingvariants of these β subunits, a wide variety of different glycoproteinhormone activities may be obtained.

In another aspect, the invention is directed to a glycosylated ornonglycosylated protein of the formula:β¹-(linker¹)_(m)-α-(linker²)_(n)-²  (1);β¹-(linker¹)_(m)-β²-(linker²)_(n)-α  (2);α-(linker¹)_(m)-β¹-(linker²)_(n)-β²  (3);β²≈α-(linker)_(m)-β¹  (4);orβ¹-(linker)_(m)-α≈β²  (5)

wherein each of β¹ and β² has the amino acid sequence of the β subunitof a vertebrate glycoprotein hormone or a variant of said amino acidsequence, wherein said variants are defined herein. “α” designates the αsubunit of a vertebrate glycoprotein hormone or a variant thereof;“linker” refers to a covalently linked moiety that spaces the β¹ and β²subunits at appropriate distances from the a subunit and from eachother. “≈” is a noncovalent link. Each of m and n is independently 0 or1.

In all of the foregoing cases, the compositions of the inventionpreserve conformation so that inclusion of the entire subunits in thecompositions is unnecessary. Thus, the invention includes compositionsof formulas (1)-(5) that comprise fragments of the α and/or β subunitswherein these forms retain the biological activity exhibited by thecorresponding forms which contain the complete subunits.

It will be noted that the compounds of formulas (1)-(5) could further bemodified to contain additional covalently linked β subunits. Thus,compounds of formulas (2) or (3) may be associated noncovalently with anadditional β subunit; the compositions of formulas (4) or (5) maycontain additional β subunits in the covalent chain. In addition, othernon-covalent associations, such as that of a β-β dimer with α or an α-αdimer with β,could be employed.

In other aspects, the invention is directed to methods to produce thecompositions of the invention, to pharmaceutical formulations containingthe compositions of formulas (1)-(5), and to methods for their use.Antibodies specific for these compositions are also included in theinvention.

MODES OF CARRYING OUT THE INVENTION

Four “glycoprotein” hormones in humans provide a family which includeshuman chorionic gonadotropin (hCG), follicle stimulating hormone (FSH),luteinizing hormone (LH), and thyroid stimulating hormone (TSH). As usedherein, “glycoprotein hormones” refers to all the members of this familyas they occur in humans and other vertebrates. All of these nativehormones are heterodimers comprised of α subunits which, for a givenspecies, are identical in amino acid sequence among the group, and βsubunits which differ according to the member of the family. Thus,normally these native glycoprotein hormones occur as heterodimerscomposed of α and β subunits that are associated but not covalentlylinked. Most vertebrates produce FSH, TSH and LH; chorionic gonadotropinhas been found only in primates, including humans, and in pregnantmares.

In animals, the α and β subunits of each hormone are encoded indifferent genes and are synthesized separately and then assembled intothe noncovalent heterodimeric complex. In the compounds of theinvention, at least one β subunit is directly linked to the α subunit ina single-chain primary structure. The three dimensional conformationconferred by secondary and tertiary structural considerations issufficiently similar to the native heterodimeric form to permit thefunctionality of the glycoprotein hormone represented by the β subunitto be exhibited. An additional β subunit is linked to this single chaineither covalently (formulas (1)-(3)) or by a noncovalent link of thetethered α subunit to an additional β subunit.

By suitable variation of the structures of the β subunits, thecompositions of the invention may have agonist and/or antagonistactivity “corresponding” to that of the native hormone; for example, thecompounds may exhibit antagonist activity with respect to a receptor forone of the glycoprotein hormones, but agonist activity for the receptorof another, or may have agonist or antagonist activity for both. Thespectrum of the activities exhibited by the compounds of the inventionwill be dependent on the selection of the individual α and β subunitsand the variants employed as well as the nature of the linker moietiesand the orientation of the α and β subunits.

In the compounds of formulas (1), (2) or (3), all three of the subunitsare covalently linked; the compositions of formulas (4) and (5) containa single chain β-α or α-β covalently linked dimer. The covalent linkagein each case is proximal to the N- or C-terminus of each subunit andmay, in the case of any two subunits, may be head-to-head (i.e.,proximal to the N-terminus of both components), tail-to-tail (i.e.,proximal to the C-terminus of both components), or, most preferably,head-to-tail, wherein the N-terminus of one subunit is covalently linkedto the C-terminus of the other. Fusion proteins which comprisehead-to-tail linkages can readily be prepared using standard recombinanttechniques provided all of the amino acids in the subunits and anylinkers are encoded by the gene. Alternatively, the compounds of theinvention can be prepared synthetically in which case, in addition tothe head-to-tail configuration, linkers may be employed to bind thesubunits proximal to their respective termini. Bifunctional linkers,including both heterobifunctional and homobifunctional types, areavailable from Pierce Chemical Company, Rockford, Illinois. Linkerswhich provide capacity to link two amino groups, or two carboxyl groups,or a carboxyl group and an amino group are available. If the linkage isnot precisely at the N-terminus, an amino acid which provides afunctional group containing side-chain will be required at a positionproximal to the terminus to be linked.

Thus, preferred embodiments of the invention, the compounds of formulas(1), (2) or (3) are fusion proteins wherein the α and β subunits arelinked head-to-tail either directly or through peptide linkers, whereonly gene-encoded amino acids comprise the sequence. These can besynthesized recombinantly. In another preferred embodiment of theinvention, the compositions of formulas (4) and (5) comprise asingle-chain form wherein the α and β subunits are linked head-to-taileither directly or through peptide linkers and an additional β subunitnoncovalently linked to the tethered α subunit, where only gene-encodedamino acids comprise the multiple domain complex. This complex, too, canbe synthesized recombinantly. However, it is unnecessary to restrict thecompositions of the invention in this manner; the α and β subunits aswell as the linkers may include amino acids that are not gene encoded.In addition, the linkers may be other than peptide-such as dicarboxylicacids or anhydrides, diamines, or bifunctional linkers such as thosesold by Pierce Chemical Co., Rockford, IL and the like. In addition, thesubunits of the single-chain form may be linked either directly orthrough a linker in a head-to-head or tail-to-tail configuration as wellas a head-to-tail configuration as would be required in a fusionprotein. Under these circumstances, for a head-to-head configuration,two amino groups may be linked through an anhydride or through anydicarboxylic acid derivative; two carboxyl groups can be linked throughdiamines or diols using standard activation techniques.

However, for convenience the most preferred form is a head-to-tailconfiguration wherein standard peptide linkages suffice and thesingle-chain form can be prepared as a fusion protein recombinantly orusing synthetic peptide techniques either in a single sequence ofreactions or, preferably, ligating individual portions of the entiresequence.

Whatever the embodiment, the α and β subunits are joined to theremainder of the molecule at positions proximal to their N and Ctermini. It is preferred that these subunits be linked directly at theirtermini, however this linkage may simply be “proximal.” In general,“proximal” indicates a position that is in within 10 amino acids,preferably within five amino acids, more preferably within two aminoacids of the terminus, and most preferably at the terminus per se. Asnoted above, where the linkage is other than at the N- or C-terminus perse, a side-chain functional group must be provided at a positionproximal to the appropriate terminus.

The Subunit Components

As used herein, the common a subunit, and the FSH, LH, TSH, and CGβsubunits as well as the compositions of the invention have theirconventional definitions and refer to the proteins having the amino acidsequences known in the art per se, or allelic variants thereof,regardless of the glycosylation pattern exhibited or otherderivatization of the amino acid side chains.

“Native” forms of these peptides are those which have the amino acidsequences as are isolated from the relevant vertebrate tissue, and havethese known sequences per se, or those of their allelic variants.

“Variant” forms of these proteins and of CTP units are those whichcorrespond to the native subunit but have deliberate alterations,including truncations, in amino acid sequences of the native protein,produced by, for example, site-specific mutagenesis or by otherrecombinant manipulations, or which are prepared synthetically.

The resulting “variants” may behave as agonists or antagonists. Theagonists may have enhanced activity as compared to the native form ordiminished activity. By adjusting the level of activity in the two βsubunits included in the compositions of the invention, variations inthe effective ratios of hormones may be achieved. For example, bysupplying an LH activity with diminished activity but a FSHβ subunitwith native or enhanced activity, the ratio of FSH/LH activity can beenhanced.

The alterations that result in “variants” consist of 1-10, preferably1-8, and more preferably 1-5 amino acid changes, including deletions,insertions, and substitutions, most preferably conservative amino acidsubstitutions. The resulting variants must retain an activity whichaffects the corresponding activity of the native hormone—i.e., eitherthey must retain the biological activity of the native hormone to whichthey correspond so as to behave as agonists, or they must behave asantagonists, generally by virtue of being able to bind the receptors forthe native hormones but lacking the ability to effect signaltransduction.

“Conservative substitution” means, in the conventional sense, asubstitution wherein the residue substituted is of the same generalamino acid category as that for which substitution is made. Amino acidshave been classified into such groups, as is understood in the art, by,for example, Dayhoff, M. et al., Atlas of Protein Sequences andStructure (1972) 5:89-99. In general, acidic amino acids fall into onegroup; basic amino acids into another; neutral hydrophilic amino acidsinto another; and so forth. More specific classifications are set forthin WO96/05224 incorporated by reference above.

One set of preferred variants is that wherein the glycosylation sites ofeither the α or β subunits or both have been altered. Some usefulvariants of the hormone quartet described herein are set forth in U.S.Pat. No. 5,177,193 issued 5 Jan. 1993, and incorporated herein byreference. As shown therein, the glycosylation patterns can be alteredby destroying the relevant sites or, in the alternative, by choice ofhost cell in which the protein is produced.

Alterations in amino acid sequence also include both insertions anddeletions. Thus, truncated forms of the hormones are included amongvariants, e.g., mutants of the α subunit which are lacking some or allof the amino acids at positions 88-92 at the C-terminus. In addition, αsubunits with 1-10 amino acids deleted from the N-terminus are included.

Variants also include those with noncritical regions altered or removed.Such deletions and alterations may comprise entire loops, so thatsequences of considerably more than 10 amino acids may be deleted orchanged. The resulting variants must, however, retain at least thereceptor binding domains with or without the regions involved in signaltransduction.

There is considerable literature on variants of the glycoproteinhormones and it is clear that a large number of possible variants whichresult both in agonist and antagonist activity can be prepared. Suchvariants are disclosed, for example, in Chen, F. et al. Molec Endocrinol(1992) 6:914-919; Yoo, J. et al. J Biol Chem (1993) 268:13034-13042;Yoo, J. et al. J Biol Chem (1991) 266:17741-17743; Puett, D. et al.Glycoprotein Hormones, Lusbader, J. W. et al. EDS, Springer Verlag NewYork (1994) 122-134; Kuetmann, H. T. et al. (ibid.) pages 103-117;Erickson, L. D. et al. Endocrinology (1990) 126:2555-2560; andBielinska, M. et al. J Cell Biol (1990) 111:330a (Abstract 1844).

Other variants include those wherein one or more cystine-bond isdeleted, typically by substituting a neutral amino acid for one or bothcysteines which participate in the link. Particularly preferred cystinebonds which may be deleted are those between positions 26 and 110 andbetween positions 23 and 72.

In addition, it has been demonstrated that the β subunits of the hormonequartet can be constructed in chimeric forms so as to provide biologicalfulnctions of both components of the chimera, or, in general, hormonesof altered biological function. Thus, chimeric molecules which exhibitboth FSH and LH/CG activities can be constructed as described by Moyle,Proc Natl Acad Sci (1991) 88:760-764; Moyle, Nature (1994) 368:251-255.As disclosed in these papers, substituting amino acids 101-109 of FSH-βfor the corresponding residues in the CG-β subunit yields an analog withboth hCG and FSH activity.

As used herein “peptide” and “protein” are used interchangeably, sincethe length distinction between them is arbitrary.

As stated above, the “variants” employed as α and β subunits in formingcompound of the invention with or without linking moieties may representthe complete amino acid sequences of the subunits or only portionsthereof.

“Variants” also include α and/or β chains which contain a CTP (or avariant of CTP) inserted into a noncritical region.

“Variants” may be agonists or antagonists of the hormone containing thecorresponding native β subunit—i.e., a “variant” of the LH β subunitwill confer agonist or antagonist activity to LH. The agonist activitymay be the same as that of the native β subunit or may be enhanced ordecreased.

“Noncritical” regions of the α and β subunits are those regions of themolecules not required for biological activity (including agonist andantagonist activity). In general, these regions are removed from bindingsites, precursor cleavage sites, and catalytic regions. Regions criticalfor inducing proper folding, binding to receptors, catalytic activityand the like should be evaluated. It should be noted that some of theregions which are critical in the case of the α and β interaction in thedimer become noncritical in single-chain units since the conformationalrestriction imposed by the molecule may obviate the necessity for theseregions. The ascertainment of noncritical regions is readilyaccomplished by deleting or modifying candidate regions and conductingan appropriate assay for the desired activity. Regions wheremodifications result in loss of activity are critical; regions whereinthe alteration results in the same or similar activity (includingantagonist activity) are considered noncritical.

It should again be emphasized that by “activity” is meant activity whichis either agonistic or antagonistic to that of the corresponding nativehormone. Thus, certain regions are critical for behavior of a variant asan antagonist, even though the antagonist is unable to directly providethe physiological effect of the hormone.

For example, for the α subunit, positions 33-59 are thought to benecessary for signal transduction and the 20 amino acid stretch at thecarboxy terminus is needed for signal transduction/receptor binding.Residues critical for assembly with the β subunit include at leastresidues 33-58, particularly 37-40.

Where the noncritical region is “proximal” to the N- or C-terminus, theinsertion is at any location within 10 amino acids of the terminus,preferably within 5 amino acids, and most preferably at the terminus perse.

As used herein, the “CTP unit” refers to an amino acid sequence found atthe carboxy terminus of human chorionic gonadotropin β subunit whichextends from amino acid 112-118 to residue 145 at the C-terminus or to aportion thereof. Thus, each “complete” CTP unit contains 28-34 aminoacids, depending on the N-terminus of the CTP.

By a “partial” CTP unit is meant an amino acid sequence which occursbetween positions 112-118 to 145 inclusive, but which has at least oneamino acid deleted from the shortest possible “complete” CTP unit (i.e.from positions 118-145). These “partial” sequences are included in thedefinition of “variants.” The “partial” CTP units preferably contain atleast one O-glycosylation site. The CTP unit contains four glycosylationsites at the serine residues at positions 121 (site 1); 127 (site 2);132 (site 3); and 138 (site 4). The partial forms of CTP useful inagonists will contain one or more of these sites arranged in the orderin which they appear in the native CTP sequence, although interveningsites may be omitted. Some nonglycosylated forms of the hormones areantagonists and are useful as such.

In some cases, CTP units may be inserted or used as linkers in tandem.By “tandem” inserts or extensions is meant that the insert or extensioncontains at least two. “CTP units.” Each CTP unit may be complete or afragment, and native or a variant. All of the CTP units in the tandemextension or insert may be identical, or they may be different from eachother.

The “linker ” is a moiety that joins the α and β sequences withoutinterfering with the activity that would otherwise be exhibited by thesame α and β chains as members of a hormone, or which alters thatactivity to convert it from agonist to antagonist activity. The level ofactivity may change within a reasonable range, but the presence of thelinker cannot be such so as to deprive the single-chain hormone ofsubstantial agonist or substantial antagonist activity. The single-chainforms must exhibit activity pertinent to the hormonal activity of thenative hormones, the elements of which form their components.

As used herein, “≈” or “noncovalent link” means a noncovalent link thatexists between the α subunit covalently linked to the β¹ subunit and anadditional β² subunit.

Preferred Embodiments of the Differentially Acting Glycoprotein Hormones

The compounds of the invention are most efficiently and economicallyproduced using recombinant techniques. Therefore, single-chain proteinscomprising those forms of α and β chains, CTP units and other linkermoieties which include only gene-encoded amino acids are preferred. Itis possible, however, as set forth above, to construct at least portionsof the single-chain hormones using synthetic peptide techniques or otherorganic synthesis techniques and therefore variants which containnongene-encoded amino acids and nonpeptide based linkers are also withinthe scope of the invention.

In one preferred embodiment, the C-terminus of the β¹ subunit iscovalently linked, optionally through a linker, to the N-terminus of themature α subunit which is in turn covalently linked optionally through alinker to the β² subunit. The linkage can be a direct peptide linkagewherein the C-terminal amino acid of one subunit is directly linkedthrough the peptide bond to the N-terminus of the other; however, inmany instances it is preferable to include a linker moiety between thetwo termini. In many instances, the linker moiety will provide at leastone β turn between the two chains. The presence of proline residues inthe linker may therefore be advantageous.

(It should be understood that in discussing linkages between the terminiof the subunits comprising the single chain forms, one or more terminimay be altered by substitution and/or deletion as described above.)

In one particularly preferred set of embodiments, the linkage ishead-to-tail and the linker moiety will include one or more CTP unitsand/or variants or truncated forms thereof. Preferred forms of the CTPunits used in such linker moieties are described hereinbelow.

In addition to their occurrence in the linker moiety, CTP and itsvariants may also be included in any noncritical region of the subunitsmaking up the single-chain hormone as described above.

While CTP units are preferred inclusions in the linker moiety, it isunderstood that the linker may be any suitable covalently bound materialwhich provides the appropriate spatial relationship between the α and βsubunits. Thus, for head-to-tail configurations the linker may generallybe a bivalent moiety such as a peptide comprising an arbitrary number,but typically less than 100, more preferably less than 50 amino acidswhich has the proper hydrophilicity/hydrophobicity ratio to provide theappropriate spacing and conformation in solution or a nonpeptide linkerwhich confers these characteristics. In general, the linker should be onbalance hydrophilic so as to reside in the surrounding solution and outof the way of the interaction between the α and β subunits or the two βsubunits. It is preferable that the linker include β turns typicallyprovided by proline residues in peptide linkers, or comprise serineand/or glycine residues. Any suitable polymer, including peptidelinkers, with the above-described correct characteristics may be used.

Particularly preferred embodiments of the single-chain forms of theinvention include in head-to-tail configuration:

βFSH-α-βFSH; α-βFSH-βLH; βFSH-α-βLH;

βLH-α-βLH; α-βLH-βFSH; βLH-α-βFSH;

βTSH-α-βTSH; βTSH-βFSH-α; βTSH-α-βFSH;

βCG-α-βCG; α-βCG-βFSH; α-βCG-βTSH; βCG-βFSH-α; βCG-α-βTSH;

βFSH-CTP-αβFSH; α-βFSH-CTP-βLH; βFSH-CTP-α-βLH;

βLH-CTP-αβLH; α-βLH-CTP-βFSH; βLH-α-CTP-βFSH;

βLH(δ115-123)-α-βFSH; βLH(δ115-123)-CTP-α-βFSH;

βCG-CTP-α CTP-βFSH-CTP-CTP;

βTSH-CTP-CTP-αβFSH-CTP-CTP;

βFSH-CTP-CTP-α-βLH; βLH-CTP-CTP-βLH-α;

βCG-CTP-CTP-α-βTSH; βCG-CTP-CTP-βLH-α;

βFSH-CTP-βLH(δ115-123)-CTP-α;

and the like. Also particularly preferred are the human forms of thesubunits. In the above constructions, “CTP” refers to CTP or itsvariants including truncations as described in PCT applicationWO96/05224.

In one embodiment, the C-terminus of the β¹ subunit is covalentlylinked, optionally through a linker, to the N-terminus of the mature αsubunit which is in turn is noncovalently linked to an additional β²subunit. The α and β subunits in the single-chain form of the presentinvention allow for the noncovalent linkage of an additional β subunitto the tethered α subunit. Particularly preferred embodiments of thecompositions of formulas (4) and (5) for use in the method of theinvention include in head-to-tail configuration (for the single-chaincomponent):

βFSH-α≈βFSH; βFSH-α≈βCG; βFSH-α≈βLH; βFSH-α≈βTSH

βCG-α≈βCG; βCG-α≈βFSH; βCG-α≈βLH; βCG-α≈βTSH

βLH-α≈βLH; βLH-α≈βFSH; βLH-α≈βCG; βLH-α≈βTSH

βTSH-α≈βTSH; βTSH-α≈βCG; βTSH-α≈βLH; βTSH-α≈βFSH;

βFSH≈α-βFSH; βCG≈α-βCG; βLH≈α-βFSH; βTSH≈α-βFSH;

βCG≈α-βCG; βFSH≈α-βCG; βLH≈α-βCG; βTSH≈α-βCG;

βLH≈α-βLH; βFSH≈α-βLH; βCG≈α-βLH; βTSH≈α-βLH;

βTSH≈α-βTSH; βCG≈α-βTSH; βLH≈α-βTSH; βFSH≈α-βTSH. and the like.Therefore, in one embodiment of the invention, the tethered β subunitand the additional β subunit will differ from one another. For example,if the tethered β subunit is a β subunit of FSH or a variant and thenoncovalently linked β subunit is the β subunit of CG or a variant, theresulting compound will have the ability to act upon the FSH and CGreceptors simultaneously. The noncovalently linked β subunit may haveagonist or antagonist activity, independent of the activity of thetethered β subunit. Additionally, the additional β subunit may have adifferent circulating half-life from that of the tethered β subunit.This difference in the circulating half-lives of the β subunits allowsfor varying degrees of activity with respect to time.

Another preferred embodiment of the invention is where the additional βsubunit and the tethered β subunit are the same or variants of eachother. For example, a covalently linked FSHβ subunit and an additionalnoncovalently linked βFSH subunit. An embodiment of this type would havethe effect of increasing the agonist or antagonist activity. Theactivity would greatest during the duration of the shorter circulatinghalf-life. Due to the longer circulating half-life of the tethered βsubunit (when the β subunits are otherwise identical), when thenoncovalently linked β subunit is no longer effective, the single-chainform will still have activity but to a lesser degree.

Another embodiment of the invention is where one β subunit is mutated tohave reduced or greater activity than the other β subunit. For example,a tethered β subunit having LH antagonist activity in combination with aβ subunit having FSH agonist activity would have the effect ofincreasing the FSH/LH ratio suitable for follicle development andfertility. If a shorter circulating half-life of the LH activity isdesired, then the tethered β subunit would have FSH activity and theother β subunit would have LH activity.

While for human use, the human forms of the α and β subunits aredesirable, it should be noted that the corresponding forms in othervertebrates are useful in veterinary contexts. Thus, the FSH, TSH and LHsubunits characteristic of bovine, ovine, equine, porcine, feline,canine, and other species are appropriate to indications affecting thesespecies per se.

In some embodiments, an additional drug may be included in the linkermoiety. Such drugs may be peptides or proteins such as insulin-likegrowth factors; epidermal growth factors; acidic and basic fibroblastgrowth factors; platelet-derived growth factors; the various colonystimulating factors, such as granulocyte CSF, macrophage-CSF, and thelike; as well as the various cytokines such as IL-2, IL-3 and theplethora of additional interleukin proteins; the various interferons;tumor necrosis factor; and the like. Suitable cleavage sites for therelease of these drugs may be included, such as target sequences forproteases whose target sites are not present in the α and β subunits.Peptide- or protein-based drugs have the advantage that the entireconstruct can readily be produced by recombinant expression of a singlegene. Also, small molecule drugs such as antibiotics,antiinflammatories, toxins, and the like can be used.

In general, the drugs included within the linker moiety will be thosedesired to act in the proximity of the receptors to which the hormonesordinarily bind. Suitable provision for release of the drug frominclusion within the linker will be provided, for example, by alsoincluding sites for enzyme-catalyzed lysis as further described underthe section headed Preparation Methods hereinbelow.

In addition, if desired, the amount of time that the drug is active andcirculating can be limited to the shorter circulating half-life of thenoncovalently linked β subunit. This may be achieved by including thedrug within the noncovalently linked β subunit rather than within thesingle-chain form.

Other Modifications

The compounds of the invention may be further conjugated or derivatizedin ways generally understood to derivatize amino acid sequences, such asphosphorylation, glycosylation, deglycosylation of ordinarilyglycosylated forms, acylation, modification of the amino acid sidechains (e.g., conversion of proline to hydroxyproline) and similarmodifications analogous to those posttranslational events which havebeen found to occur generally.

The glycosylation status of the hormones of the invention isparticularly important. The hormones may be prepared in nonglycosylatedform either by producing them in procaryotic hosts or by mutating theglycosylation sites normally present in the subunits and/or any CTPunits that may be present. Both nonglycosylated versions and partiallyglycosylated versions of the hormones can be prepared by manipulatingthe glycosylation sites. Normally, glycosylated versions are, of course,also included within the scope of the invention.

As is generally known in the art, the compounds of the invention mayalso be coupled to labels, carriers, solid supports, and the like,depending on the desired application. The labeled forms may be used totrack their metabolic fate; suitable labels for this purpose include,especially, radioisotope labels such as iodine 131, technetium 99,indium 111, and the like. The labels may also be used to mediatedetection of the single-chain proteins in assay systems; in thisinstance, radioisotopes may also be used as well as enzyme labels,fluorescent labels, chromogenic labels, and the like. The use of suchlabels permits localization of the relevant receptors since they can beused as targeting agents for such receptors.

The compounds of the invention may also be coupled to carriers toenhance their immunogenicity in the preparation of antibodiesspecifically immunoreactive with these new modified forms. Suitablecarriers for this purpose include keyhole limpet hemocyanin (KLH),bovine serum albumin (BSA) and diphtheria toxoid, and the like. Standardcoupling techniques for linking the modified peptides of the inventionto carriers, including the use of bifunctional linkers, can be employed.

Similar linking techniques, along with others, may be employed to couplethe proteins of the invention to solid supports. When coupled, theseproteins can then be used as affinity reagents for the separation ofdesired components with which specific reaction is exhibited. Thus, theyare useful in the purification and isolation of the receptors with whichthe appropriate β subunit interacts.

Preparation Methods

Methods to construct the compounds of the invention are well known inthe art. As set forth above, if only gene encoded amino acids areincluded, and the single-chain form is in a head-to-tail configuration,the most practical approach at present is to synthesize these materialsrecombinantly by expression of the DNA encoding the desired protein orproteins. DNA containing the nucleotide sequence encoding thesingle-chain forms included in the invention compositionss, includingvariants, can be prepared from native sequences, or synthesized de novoor using combinations of these techniques. Techniques for site-directedmutagenesis, ligation of additional sequences, amplification such as byPCR, and construction of suitable expression systems are all, by now,well known in the art. Portions or all of the DNA encoding the desiredprotein can be constructed synthetically using standard solid phasetechniques, preferably to include restriction sites for ease ofligation. Suitable control elements for transcription and translation ofthe included coding sequence can be provided to the DNA codingsequences. As is well known, expression systems are now availablecompatible with a wide variety of hosts, including procaryotic hostssuch as E. coli or B. subtilis and eucaryotic hosts such as yeast, otherfungi such as Aspergillus and Neurospora, plant cells, insect cells,mammalian cells such as CHO cells, avian cells, and the like.

The choice of host is particularly pertinent to posttranslationalevents, most particularly including glycosylation. The location ofglycosylation is mostly controlled by the nature of the glycosylationsites within the molecule; however, the nature of the sugars occupyingthis site is largely controlled by the nature of the host. Accordingly,a fine-tuning of the properties of the hormones of the invention can beachieved by proper choice of host.

A particularly preferred form of gene for the α subunit portion, whetherthe α subunit is modified or unmodified, is the “minigene” construction.As used herein, the α subunit “minigene” refers to the gene constructiondisclosed in Matzuk, M. M., et al., Mol Endocrinol (1988) 2:95-100, inthe description of the construction of pM²/CGα or pM²/α

For recombinant production, modified host cells using expression systemsare used and cultured to produce the desired protein. These terms areused herein as follows:

A “modified” recombinant host cell, i.e., a cell “modified to contain”the recombinant expression systems of the invention, refers to a hostcell which has been altered to contain this expression system by anyconvenient manner of introducing it, including transfection, viralinfection, and so forth. “Modified cells” refers to cells containingthis expression system whether the system is integrated into thechromosome or is extrachromosomal. The “modified cells” may either bestable with respect to inclusion of the expression system or theencoding sequence may be transiently expressed. In short, recombinanthost cells “modified” with the expression system of the invention refersto cells which include this expression system as a result of theirmanipulation to include it, when they natively do not, regardless of themanner of effecting this incorporation.

“Expression system” refers to a DNA molecule which includes a codingnucleotide sequence to be expressed and those accompanying controlsequences necessary to effect the expression of the coding sequence.Typically, these controls include a promoter, termination regulatingsequences, and, in some cases, an operator or other mechanism toregulate expression. The control sequences are those which are designedto be functional in a particular target recombinant host cell andtherefore the host cell must be chosen so as to be compatible with thecontrol sequences in the constructed expression system.

Secretion of the protein produced is generally desired. Thus, nucleotidesequences encoding a signal peptide are also included so as to producethe signal peptide operably linked to the desired single-chain hormoneto produce the preprotein, which upon secretion, is cleaved to releasethe mature single-chain hormone or desired β subunit. Glycoproteinhormones are normally secreted proteins and the signal sequencesincluded may be those associated with the hormones per se or may beheterologous thereto. Although not preferred, intracellular productionof the hormones could be effected by suitable manipulation of theencoding genes.

As used herein “cells,” “cell cultures,” and “cell lines” are usedinterchangeably without particular attention to nuances of meaning.Where the distinction between them is important, it will be clear fromthe context. Where any can be meant, all are intended to be included.

The protein produced may be recovered from the lysate of the cells ifproduced intracellularly, or from the medium if secreted. Techniques forrecovering recombinant proteins from cell cultures are well understoodin the art, and these proteins can be purified using known techniquessuch as chromatography, gel electrophoresis, selective precipitation,and the like.

With respect to recombinant production of the compounds of formulas(1)-(3), a single expression system comprising the nucleotide sequenceencoding the compounds of these formulas will be employed. Forcompositions of formulas (4) and (5), in general, two expressionsystems, both contained within the recombinant host, are preferablyused. Thus, an expression system for the α-(linker)_(m)-β1 orβ1-(linker)_(m)-α portion of the compound will be constructed containingthe nucleotide sequence encoding this single-chain peptide and anadditional expression system encoding β² will also be included in thecell. The two expression systems may be contained on a single vector,within the chromosome of the host cell, on separate vectors, or oneexpression system may reside in the chromosome and the other on anextrachromosomally replicating vector. Alternatively, a dicistronicexpression system containing both required encoding nucleotide sequencesmay be employed, either on an extrachromosomally replicating vector orcontained in the host cell chromosome. In still another approach, thetwo noncovalently bound components may be prepared separately andassociated under suitable in vitro conditions. Conditions favoringassembly of the compositions of formulas (4) or (5) would be familiar tothose in the art and would mimic intracellular conditions.

In addition, all or a portion of the compounds of the invention may besynthesized directly using peptide synthesis techniques known in theart. Synthesized portions may be ligated, and release sites for any drugcontained in the linker moiety introduced by standard chemical means.For those embodiments which contain amino acids which are not encoded bythe gene and those embodiments wherein the head-to-head or tail-to-tailconfiguration is employed, of course, the synthesis must be at leastpartly at the protein level. Head-to-head junctions at the naturalN-termini or at positions proximal to the natural N-termini may beeffected through linkers which contain functional groups reactive withamino groups, such as dicarboxylic acid derivatives. Tail-to-tailconfigurations at the C-termini or positions proximal to the C-terminimay be effected through linkers which are diamines, diols, orcombinations thereof.

Antibodies

The proteins of the invention may be used to generate antibodiesspecifically immunoreactive with the multiple domain glycoproteinhormones disclosed herein. These antibodies are useful in a variety ofdiagnostic and therapeutic applications.

The antibodies are generally prepared using standard immunizationprotocols in mammals such as rabbits, mice, sheep or rats, and theantibodies are titered as polyclonal antisera to assure adequateimmunization. The polyclonal antisera can then be harvested as such foruse in, for example, immunoassays. Antibody-secreting cells from thehost, such as spleen cells, or peripheral blood leukocytes, may beimmortalized using known techniques and screened for production ofmonoclonal antibodies immunospecific with the proteins of the invention.

“Antibodies”, which may be from any animal species, including humans,include any fragment which retains the required immunospecificity, suchas F_(ab), F_(ab′), or F_((ab′)) ₂ F_(v) and so forth. Thus, theantibodies may also be prepared using recombinant techniques, typicallyby isolating nucleotide sequences encoding at least the variable regionsof monoclonal antibodies with the appropriate specificity andconstructing appropriate expression systems. This approach permits anydesired modification such as production of F_(v) forms, chimeric forms,“humanized” forms and the like.

By “immunospecific for the proteins of the invention” is meantantibodies which specifically bind the referent compound of theinvention, but not the native glycoprotein hormones or any of theincluded subunits per se or any single-chain units which include only asingle β subunit within the general parameters considered to determineaffinity or nonaffinity. It is understood that specificity is a relativeterm, and an arbitrary limit could be chosen, such as a difference inspecific binding of 100-fold or greater. Thus, an immunospecificantibody included within the invention is at least 100 times morereactive with the multiple domain complex than with the correspondingnative hormone, prior art single-chain forms or separate subunits. Suchantibodies can be obtained, for example, by screening for those thatbind the invention compounds and discarding those that also bind thenative hormones, subunits or prior art single-chain forms set forth inWO95/22340 and WO96/05224.

Formulation and Methods of Use

The proteins of the invention are formulated and administered usingmethods comparable to those known for the heterodimers generallycorresponding to them. Thus, formulation and administration methods willvary according to the particular hormone or hormone combination used.However, the dosage level and frequency of administration may be alteredas compared to the native heterodimers, especially if CTP units arepresent in view of the extended biological half-life due to itspresence.

Formulations for proteins of the invention are those typical of proteinor peptide drugs such as found in Remington's Pharmaceutical Sciences,latest edition, Mack Publishing Company, Easton, Pa. Generally, proteinsare administered by injection, typically intravenous, intramuscular,subcutaneous, or intraperitoneal injection, or using formulations fortransmucosal or transdermal delivery. Other modes of delivery, such assuppositories, may also be employed. These formulations generallyinclude a detergent or penetrant such as bile salts, fusidic acids, andthe like. These formulations can be administered as aerosols orsuppositories or, in the case of transdermal administration, in the formof skin patches. Oral administration is also possible provided theformulation protects the peptides of the invention from degradation inthe digestive system.

Optimization of dosage regimen and formulation is conducted as a routinematter and as generally performed in the art. These formulations canalso be modified to include those suitable for veterinary use.

The compositions of the invention may be used in many ways, mostevidently as substitutes for the native forms of the hormones. Thus, thecompositions of the invention can be used in treatment of infertility,as aids in in vitro fertilization techniques, and other therapeuticmethods associated with the native hormones or their subunits. Thesetechniques are applicable to humans as well as to other animals. Thechoice of the composition in terms of its species derivation will, ofcourse, depend on the subject to which the method is applied. It will berealized that the ability to act differentially which is conferred onthe compositions of the invention confers opportunities for therapiesthat have previously been unavailable.

The invention compositions are also useful as reagents in a mannersimilar to that employed with respect to the native heterodimers.

In addition, the compounds of the invention may be used as diagnostictools to detect the presence or absence of antibodies that bind to thenative proteins to the extent such antibodies bind to the relevantportions of these multiple domain compounds in biological samples. Theyare also useful as control reagents in assay kits for assessing thelevels of these hormones in various samples. Protocols for assessinglevels of the hormones themselves or of antibodies raised against themare standard immunoassay protocols commonly known in the art. Variouscompetitive and direct assay methods can be used involving a variety oflabeling techniques including radio-isotope labeling, fluorescencelabeling, enzyme labeling and the like.

The compounds of the invention are also useful in detecting andpurifying receptors to which the native hormones bind. Thus, thecompounds of the invention may be coupled to solid supports and used inaffinity chromatographic preparation of receptors or antihormoneantibodies. The resulting receptors are themselves useful in assessinghormone activity for candidate drugs in screening tests for therapeuticand reagent candidates. Of course, account must be taken of the dualspecificity of the β subunits in any of these compounds where the βsubunits are different. However, where the two β subunits are identical,they offer a powerful affinity purification tool for the relevantreceptor.

Finally, the antibodies uniquely reactive with the compounds of theinvention can be used as purification tools for isolation of thesematerials in their subsequent preparations. They can also be used tomonitor levels of these compounds administered as drugs.

The following examples are intended to illustrate but not to limit theinvention.

EXAMPLE 1 Preparation of CGβ-α-CTP-FSHβ

A nucleotide sequence encoding the title compound was prepared using theavailable nucleotide sequences for the relevant portions of thesubunits. The CGβ region encodes the 145 amino acids of human CGβ; the αsubunit-encoding nucleotide sequence encodes the 92 amino acids of humana as the minigene; the CTP-encoding sequence encodes 28 amino acidsrepresenting positions 118-145 of human chorionic gonadotropin; and theFSHβ encoding region encodes the 111 amino acids of the human FSHβsubunit.

An amplified fragment containing CGβ exon 3, the a minigene, CTP andβFSH was inserted into the SalI site of pM²HA-CGβexon1,2 an expressionvector which is derived from pM² and containing CGβ exons 1 and 2 in themanner described by Sachais, β Biol Chem (1993) 268:2319. pM² containingCGβ exons 1 and 2 is described in Matzuk, M. M. et al. Proc Natl AcadUSA (1987) 84:6354-6358 and Matzuk, M. M. et al. J Cell Biol (1988)106:1049-1059. First, a fragment containing the α minigene downstream ofCGβ exon 3 was inserted into this vector to obtain pM²-HACGβα.pM²-HACGβα was then cleaved with ScaI and ligated with ScaI restrictedpBIIKS(+)α-CTP-FSH. The resulting expression vector pM²-HACGβ-α-CTP-FSHproduces the title compound when inserted into a suitable host.

EXAMPLE 2 Production and Activity of the CGβ-α-CTP-FSHβ

The expression vector constructed in Example 1 was transfected intoChinese hamster ovary (CHO) cells and production of the protein wasassessed by immunoprecipitation of radiolabeled protein on SDS gels.

The culture medium was collected, concentrated and tested for binding tothe human LH receptor (expected to bind the βCG-α portion).

For this assay, the LH receptor was prepared by inserting the cDNAencoding the entire human LH receptor into the expression vector pCMX(Oikawa, J. X-C et al. Mol Endocrinol (1991) 5:759-768). Exponentiallygrowing 293 cells were transfected with this vector using the method ofChen, C. et al. Mol Cell Biol (1987) 7:2745-2752, resulting inexpression of the LH receptor at the surface.

In the assay, the cells expressing human LH receptor (2×10⁵/tube) wereincubated with 1 ng of labeled hCG in competition with increasingconcentrations of unlabeled hCG or increasing amounts of the sample tobe tested at 22° C. for 18 hours. The decrease in label in the presenceof sample measures the binding ability in the sample. In this assay,with respect to the human LH receptor in 293 cells, the heterodimerichCG had an activity typical of wild-type as previously determined andthe CGβ-α-CTP-FSHβ-containing medium also showed activity. These resultsare shown in FIG. 1. As shown, both heterodimeric (solid squares) hCGand the bifunctional single-chain protein of the invention (solidcircles) competed successfully with labeled hCG for LH receptor. Thebifunctional compound is less potent due to the modification of the αsubunit carboxy terminus.

Also shown in FIG. 1 are the results of the assay wherein varyingamounts of a culture supernatant derived from cells modified to containtwo expression systems was tested. One expression system produced asingle chain FSHβ-α; the other produced the β subunit of hCG. Theresulting noncovalently associated single-chain FSHα-β/CGβ complex(solid triangles) also successfully competed for binding.

In a similar manner, the supernatant from the culture medium containingCGβ-α-CTP-FSHβ was tested for binding to the receptor for FSH, expressedin 293 cells. The assay was conducted in the manner described above,except that cells expressing the human FSH receptor were substituted forthose expressing human LH receptor and labeled FSH was used as thecompetitor. The results of this assay are shown in FIG. 2.

As shown, the single-chain title compound (solid circles) competedsuccessfully with FSH (solid squares) for binding. In an unrelatedexperiment, also shown in FIG. 2, the mixture of a different type ofcomplex—i.e., single-chain FSHβ-α noncovalently associated withCGβ—which is mixed with uncomplexed excess single-chain FSHβ-α (solidtriangles), was an excellent competitor.

EXAMPLE 3 Construction of Additional Expression Vectors

In a manner similar to that set forth in Example 1, expression vectorsfor the production of single-stranded bifunctional FSHβ-CTP-α-CG β;α-FSHβ-CTP-CG β, CG β-βFSH-CTP-α, and βLH-CTP-βFSH-CTP-α are preparedand transfected into CHO cells. The culture supernatants are culturedand tested as described above with respect both to the LH and FSHreceptors. These compounds, too, show ability to bind both receptors.

EXAMPLE 4 Preparation of FSHβ-α≈CGβ

To create the compound, FSHβ-α≈CGβ, the expression vectors for theproduction of a single-chain FSHβ-α, and a human CGβ subunit wereprepared and co-transfected into Chinese hamster ovary (CHO) cells in amanner similar to the methods disclosed in the PCT application of theinventor herein, WO96/05224 published 22 Feb. 1996. The CGβ subunitcombined with FSHβ-α to form a noncovalent FSHβ-α≈CG complex. Theproduction and activity of the noncovalent FSHβ-α≈CG complex wasassessed by immunoprecipitation of radiolabeled protein on SDS gels.

The culture medium was collected, concentrated and tested for binding tothe human LH receptor (expected to bind the βCG portion) and the humanFSH receptor (expected to bind the FSHβ-α).

The results indicate that the noncovalent FSHβ-α≈CG complex displays CGand FSH-specific receptor binding. These data indicate that the αsubunit of the tether, although covalently linked to the FSHβ domain,can functionally interact with a different β subunit and the presence ofthis configuration does not abolish bioactivity. Other multiple domaincomplexes such as βFSH-α≈βLH, βCG-α≈βLH, βLH-α≈βTSH, and βTSH-α≈βFSH mayalso be generated in a similar fashion.

EXAMPLE 5 Use of Differentially Acting Compounds to Regulate HormoneRatios

The differentially acting compounds are formulated and administeredusing methods comparable to those known for the native hormonescorresponding to them.

A. Increasing fertility by increasing the FSHILH ratio and/or byincreasing CG.

Increased fertility may be achieved by increasing the FSH/LH ratio witha compound of the formula (1)-(5) wherein one β subunit has weakened LHagonist activity or LH antagonist activity and the other β subunit has(optionally enhanced) FSH agonist activity. The LHβ subunit may bemodified to have lower agonist or antagonist activity by eliminatingglycosylation of the LHβ chain or by point mutations, whereas the FSHβsubunit may be used in its native form or modified to have increasedagonist activity. The resulting compound will have the ability toincrease FSH hormone levels while simultaneously decreasing LH hormonelevels. When a therapeutic dose of this compound is administered to amammal during the follicular phase of the menstrual cycle, increasedfertility results.

Additionally, it may be advantageous to make the circulating half-lifeof the FSH subunit longer than the LHβ circulating half-life. This isaided by using a FSHβ-α≈LHβ compound.

Increased fertility may also be achieved by increasing CG hormone levelsand decreasing LH hormone levels by administering a compound of theformula (1)-(5) wherein one β subunit has LH antagonist activity orlowered LH agonist activity and the other β subunit has CG agonistactivity. Additionally, the CGβ subunit may be engineered to have agreater binding affinity than LHβ to the CG/LH receptor. Whenadministered at appropriate times and doses, the FSH/LH ratio willincrease to ratio favorable for fertility and the CG activity will alsoincrease to levels favorable for pregnancy.

Likewise, fertility may be increased with a compound of the formula(1)-(5) wherein one β subunit has FSH agonist activity and the other βsubunit has CG agonist activity. Administration of these complexes willincrease the FSH/LH ratio favorable for fertility and also increase CGactivity to levels favorable for pregnancy.

It may be advantageous to make the circulating half-life of one βsubunit longer than the other, which is aided by using a composition ofthe formula (4) or (5).

B. Inducing infertility by decreasing the FSH/LH ratio and/or decreasingCG.

Infertility may be induced by decreasing the FSH/LH ratio with theadministration of a compound of the formula (1)-(5) wherein one βsubunit has LH agonist activity and the other β subunit has FSHantagonist or reduced agonist activity. For this application, the LHβsubunit may be modified to have enhanced agonist activity by alteringthe glycosylation of the LHβ chain or by point mutations, whereas theFSHβ subunit may be modified to have lowered agonist activity. Theresulting compound will have the ability to increase LH activity whilesimultaneously decreasing FSH activity, thereby lowering the FSH/LHratio to a level unfavorable for fertility.

Infertility may also be induced by decreasing the FSH/LH ratio with theadministration of a compound of the formula (1)-(5) wherein one βsubunit has LH agonist activity and the other β subunit has CG agonistactivity. Administration of this compound would result in a low FSH/LHratio and a high CG hormone level, both of which are unfavorable forfertility and pregnancy.

As above, it may be advantageous to make the circulating half-life ofone β subunit longer than the other, by using a composition of theformula (4) or (5). It may also be advantageous to vary the bindingaffinities of the β subunits.

C. Treating polycystic ovarian syndrome by decreasing the LH/FSH ratio.

Polycystic ovarian syndrome is characterized by incomplete follicledevelopment and abnormal ovulation. Women suffering from this diseasehave elevated androgens and a high ratio of LH/FSH relative to normalfertile women. Thus, at the time of the menstrual cycle when folliculardevelopment is supposed to be normally initiated, administration of acompound of the formula (1)-(5) wherein one β subunit has lowered LHagonist activity or antagonist activity and the other β subunit has FSHagonist activity will boost follicle development and induce ovulation.Since the administration of an FSH agonist has the risk of causinghyperstimulation, it is preferable that FSHβ subunit is thenoncovalently linked β subunit having the shorter circulating half-lifeand/or the FSHβ subunit is engineered to have a decreased bindingaffinity.

1. An isolated glycosylated or nonglycosylated composition of theformulaβ²≈α-(linker)_(m)-β¹  (1); orβ¹-(linker)_(m)-α≈β²  (2) wherein each of β¹ and β² has the amino acidsequence of the β subunit of a vertebrate glycoprotein hormone, or avariant thereof; “α” has the amino acid sequence of the α subunit of avertebrate glycoprotein hormone or a variant thereof; “linker” is alinker moiety; and “≈” is a noncovalent link between α and β²; m is 0 or1; wherein one of β¹ and β² confers agonist activity and the otherconfers antagonist activity.
 2. The composition of claim 1, wherein β¹and β² are β subunits of different glycoprotein hormones or variantsthereof.
 3. The composition of claim 1, wherein β¹ and β² exhibitdifferent biological half-lives.
 4. The composition of claim 1, whereinone of β¹ and β² confers FSH agonist activity and the other confers LHantagonist activity; or wherein one of β¹ and β² confers LH antagonistactivity and the other confers CG agonist activity.
 5. The compositionof claim 1, wherein one of β¹ and β² confers FSH antagonist activity andthe other confers LH agonist activity; or wherein one of β¹ and β²confers FSH antagonist activity and the other confers CG antagonistactivity; or wherein one of β¹ and β² confers LH agonist activity andthe other confers CG antagonist activity.
 6. The composition of claim 1,wherein one of β¹ and β² confers FSH agonist activity and the otherconfers LH antagonist activity.
 7. A pharmaceutical formulation whichconsists essentially of an effective amount of the composition of claim1 in admixture with at least one pharmaceutically acceptable excipient.